This invention relates to masonry and more particularly to a machine for the manufacture of cement stabilized pressed earth masonry products such as bricks, blocks and tiles.
Masonry products have, of course, been used since the beginning of recorded time. The manufacture of such products has developed principally along three lines; firstly the quarrying of stone; secondly using a process in which clay is moulded and then burnt by firing; and thirdly, the mixing of sand, cement and gravel to produce a concrete block.
To a somewhat lesser extent, "rammed" earth has long been used to produce bricks and monolithic structures, known as "adobe" and "pise" respectively, the earth usually being taken from the immediate vicinity.
It will be appreciated that to achieve a serviceable product from the burnt clay process, suitable clays are required. However these often are not readily obtainable. This material must be prepared and moulded, using very expensive equipment, prior to drying the moulded product and subsequently firing it in a kiln. The process is quite a complex and costly one, and requires not only expensive machinery and considerable expenditure of energy, but also a large area of land for the manufacturing plant.
Similarly, the raw materials of concrete blocks, namely sand, gravel and cement, can be quite expensive and require transportation to the site. The raw product cannot be stacked during curing and hence, once again, a large factory area is required. Moreover, concrete blocks are highly permeable and cannot be used without an external sealing coat.
Adobe and pise have self-evident inherent problems, particularly relating to structural strength and longevity.